Coating thickness measurement

Reliably evaluating coatings – ensuring protective effectiveness

Coatings fulfill various functions in technical applications: corrosion protection, wear protection, electrical insulation, or decorative requirements. Coating thickness significantly influences the service life and functionality of a component.

A coating thickness that is too low can impair the protective effect, while a coating thickness that is too high can lead to fit problems or material stresses. Coating thickness measurement ensures that the specified tolerances are met.

Depending on the material combination and type of coating, different measurement methods are used – non-destructive or destructive, point-based or area-based.

Which coatings or characteristics are tested?

The following characteristics, among others, can be determined as part of coating thickness measurement:

• Thickness of electroplated coatings (e.g., zinc, nickel, chromium)
• Paint or powder coatings
• Anodized or oxide layers
• Multi-layer coating systems

The selection of the appropriate measurement method depends on the substrate material, coating material, component geometry, and required measurement accuracy.

Testing methods used

Coating thickness measurement can be performed using various methods:

• Eddy current testing (ET) – for measuring non-conductive coatings on conductive substrates
• Magnetostrictive methods – for determining non-magnetic coatings on ferromagnetic substrates
• X-ray-based methods (RT) – for analyzing multi-layer systems or complex coating structures
• Metallographic section analysis – for destructive microstructural testing to precisely determine the coating thickness

Depending on requirements, measurements are performed on a random basis, during series production, or as a 100% inspection.

Typical applications of coating thickness measurement

Coating thickness measurement is used in particular:

• After electroplating or thermal coating processes
• In incoming inspection of coated components
• For process monitoring in series production
• As part of complaint analyses
• For corrosion protection or service life assessments

Industries and application areas of coating thickness measurement

Coating thickness measurement is relevant in all industrial sectors where coated components are critical to function or safety, including:

• Automotive and supplier industry
• Aerospace
• Machinery and plant engineering
• Energy and power plant sector
• Electronics industry
• Metal processing and surface technology

The specific design of the test depends on the component, material, accessibility, and the respective quality requirements.

Conducting coating thickness measurement at Technomix

Coating thickness measurement is performed based on clearly defined test plans and agreed-upon specifications. Depending on the material combination and measurement requirements, the appropriate method is selected and calibrated.

The results are documented and statistically evaluated as needed. The process is integrated into our quality management system in accordance with DIN EN ISO 9001.